Longitudinal carriage drive for co-ordinates tables in machine tools, particularly punching machines

ABSTRACT

A longitudinal carriage drive for co-ordinates tables in machine tools for impelling the carriages on co-ordinates tables, particularly the longitudinal carriage, with the transverse carriage moving thereupon transversely to the longitudinal axis of the machine, and to the material to be punched held fast thereto, in which a power transmission by two screw-threaded spindles is provided to the left and right of the center of the machine, which receive their drive synchronously from a motor arranged at about the middle of the table.

United States Patent Bredow [451 Mar. 21, 1972 [54] LONGITUDINALCARRIAGE DRIVE FOR CO-ORDINATES TABLES IN MACHINE TOOLS, PARTICULARLYPUNCHING MACHINES [72] Inventor: Walter Bredow, Alfeld an der Leine,

Germany [73] Assignee: C. Behrens Aktlengesellschait,

sl n sr. .i i9 many [22] Filed: Sept. 3, 1969 [21] Appl. No.: 854,851

[30] Foreign Application Priority Data Sept. 17, 1968 Germany ..P 17 77180.1

[52] U.S. Cl ..72/l, 72/419, 83/409 [51] Int. Cl. ..B2ld 55/00, B2ld43/00, 826d 7/06 [58} Field of Search ..72/1, 419; 83/409; 226/] l,

[56] References Cited UNITED STATES PATENTS 2,887,914 5/1959 Zeunert..72/] 2,901,245 8/1959 Hensley ....83/409 X 3,330,175 7/ 1967 Bridges....83/409 X 3,391,840 7/1968 King ....226/l1 3,429,491 2/1969 Windley..226/|1 Primary Examiner-Charles W. Lanham Assistant Examiner-R. M.Rogers Attorney-Holman &. Stems ABSTRACT A longitudinal carriage drivefor co-ordinates tables in machine tools for impelling the carriages onco-ordinates tables, particularly the longitudinal carriage, with thetransverse carriage moving thereupon transversely to the longitudinalaxis of the machine, and to the material to be punched held fastthereto, in which a power transmission by two screwthreaded spindles isprovided to the left and right of the center of the machine, whichreceive their drive synchronously from a motor arranged at about themiddle of the table.

3 Claims, 3 Drawing Figures PATENTEBMARZ] I972 3,650,133

sum 1 OF 3 lnrenfar:

6004 nm B/FEDa w PATENTEUMARZI I972 SHEET 2 OF 3 lnrenlonw 4 rat BREW 04PATENTEUMMI I972 SHEET 3' [1F 3 lilllllll k lnren/ar: LUALTER BREDaw37., k (T /M7 ATTDRA/EYS LONGITUDINAL CARRIAGE DRIVE FOR CO- ORDINATESTABLES IN MACHINE TOOLS, PARTICULARLY PUNCHING MACHINES BACKGROUND OFTHE INVENTION This invention relates to the longitudinal carriage drivefor coordinates tables in machine tools, particularly punching orstamping machines, for the transporting of the carriages on thecoordinates tables, particularly of the longitudinal carriage, with thetransverse carriage moving thereupon transversely to the longitudinalaxis of the machine, and with the material to be punched or stamped heldfast thereon, with power-transmission by screw-threaded spindles. Theinvention is particularly advantageous with revolving punches, withwhich the need arises to improve the accuracy of the positioning of thecoordinates tables, and to provide the presumptions for the supervisionof this accuracy.

SUMMARY OF THE INVENTION The invention consists in the feature that tothe left and right of the center of the machine two threaded spindlesare arranged, which receive their drive synchronously from a commondriving motor arranged on about the center of the table. It has beenfound particularly advantageous in this case to employ ball rotaryspindles, which, in consequence of the initial stress of the ballbearings, ensure running practically free from backlash in thetransmission of the driving forces. The adoption of such spindles alsohas the advantage that the coefficient of friction of the drivingspindle is completely invariable.

In a preferred form of construction of the invention, the driving motorand the power-transmitting means between this motor and the threadedspindles are arranged symmetrically about the Y-axis of the longitudinalcarriage. Such an arrangement provides particularly advantageouspresumptions for the accommodation of monitoring appliances, whichalready show any change of equilibrium between the drives, or even cutout the drive altogether. As power-transmitting means between the motorand the driving spindles, toothed belt gears are preferred. Such gearsprovide lightweight steel-armored expansion-free toothed belts, whichtransmit the driving forces positively and without slipping.

According to a further feature of the invention, with the toothed beltsare associated electrical measured-value receivers, for instanceelectric generators, which, upon disturbance of the state ofequilibrium, switch off the drive. It is also possible to associatelight cabinets with the toothed belts. It is obvious that with the driveaccording to the invention, the driving means that are to meet thehighest requirements as regards accuracy must remain protected againstany disturbance in operation and against overstressing. The arrangementof the monitoring appliances is promoted by the same forces and the samespeeds having to occur in each case at the same points in thesymmetrically arranged driving system. Any change in the state ofequilibrium gives rise to a response from the monitoring appliances, sothat disturbances can be directly avoided. It is obvious that by themeasures according to the invention, a considerable improvement in theaccuracy of working of punching machines is also effected, which canthereby be employed in machining operations which require particularlyhigh accuracy.

One constructional example of the invention is illustrated in theaccompanying drawings, as applied to a revolving punch, and will now befurther described. The invention is, however, also applicable topunching and stamping machines and other machine tools of a differentconstruction.

In the accompanying drawings,

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a coordinates table inside elevation; FIG. 2 shows a plan view of the coordinates table; andFIG. 3 shows the coordinates table in front elevation.

DETAILED DESCRIPTION OF THE DRAWINGS Upon underpart 1 of the table arearranged, to right and left (FIG. 3), longitudinal girders 2 and 2' forthe accommodation and guidance of a longitudinal carriage. To thelongitudinal girders 2 and 2' are bolted guiding rails 3 and supportingrails 4, upon which the complete longitudinal carriage is guided andsupported, respectively. The longitudinal carriage consists essentiallyof a cross girder 5, with a left-hand roller shoe 6 and a right-handroller shoe 6', in which supporting rollers 7 and lateral guidingrollers 8 are journaled. To the underside of the roller shoes 6 and 6'are secured holders 9 and 9' for the accommodation of the ball rotarynuts of ball rotary spindles 10, serving advantageously as a drive, fordriving the longitudinal carriage; and upon these roller shoes aresecured supporting plates 11, 11 for the material to be punched. Thesebearing surfaces thus accompany the movement of the iongitudinalcarriage.

The ball rotary spindles 10 are axially mounted in bearing shields 12and 12 and bearings 13 and 13, which are connected fast, in front andbehind, with the longitudinal girders 2 and 2' respectively.

Upon the cross girder 5 of the longitudinal carriage is secured aleft-hand bearing 14 and a right-hand bearing 15, and also a motorcasing 16, with a driving motor for a ball rotary spindle 17 of atransverse carriage 18. A ball rotary nut 19 on the spindle 17 isconnected on the other side by its holder with the transverse carriage18, and to the latter in turn is bolted a clamping rail 20. To thisagain workpiece-stretchers 21, three in number, for example, aredisplaceably secured. By these workpiece-stretchers is held material 22to be punched, consisting of a plate, represented by dot-and-dash lines,for travelling between the upper and lower turntables of rotary punches.The axial positions of the bearings of these turntables are indicated at23, and that of one of the tool stations at 24.

Between the lateral punching-material supporting plates 1 l and 11', andpivoted to the latter and moved therewith, are located transverseroller'guided punch-material supporting rails 25, which, upon thepunched material being removed towards the left (see FIG. 1), are guidedover a descending guiding curve 26 into an open space between theunderpart l of the table and the transverse girder 5 of the longitudinalcarriage and are there caught up. Guiding and connecting chains 27 forthe punched-material rails 25 are pivotally connected by theirright-hand ends 28 and 28' with the punched-material supporting plates11 and 11, and by spring-equipped tension rods 29, in the bearingshields l2, 12', which are secured, under tension, to the front ends ofthe longitudinal girders 2 and 2'.

The longitudinal carriage drive by the ball rotary spindles 10 iseffected completely without slip and with the spindles turningsynchronously, by a driving motor 41, which is connected by a bearingshield 40 with the front wall of the underpart 1 of the table, with theaid of toothed belts 42, by way of corresponding toothed disc wheels 43.It will be seen that the power transmitting means between the motor 41and the spindles are symmetrically arranged about Y-axis of thelongitudinal carriage. In connection with the toothed belts 42 arearranged measured-value receivers, for instance electrical generators44, or, optionally, light sensors 45, which respond to irregular runningof the power-transmitting means, or to breakage of a toothed belt, andthereby preclude any injury to the drive, and to the guidance of thelongitudinal carriage, by interrupting the drive.

What is claimed is:

l. A longitudinal carriage drive for coordinates tables in machinetools, particularly punching or stamping machines, for impelling thecarriages on coordinates tables, particularly a longitudinal carriage,with a transverse carriage moving thereupon transversely to thelongitudinal axis of the machine, and to material to be punched heldfast thereto, with powerin the state of equilibrium, to deactivate thedrive.

2. The longitudinal carriage drive as claimed in claim I, wherein saidelectrical measurement-value receivers are electric generators.

3. The longitudinal carriage drive as claimed in claim 1, wherein saidelectrical measurement-value receivers are light sensors.

II I I t t

1. A longitudinal carriage drive for coordinates tables in machinetools, particularly punching or stamping machines, for impelling thecarriages on coordinates tables, particularly a longitudinal carriage,with a transverse carriage moving thereupon transversely to thelongitudinal axis of the machine, and to material to be punched heldfast thereto, with powertransmission by screw-threaded spindles, theimprovement including, to the left and right of the center of themachine, two threaded spindles, a motor arranged at approximately themiddle of the table, toothed belt drives between the motor and thethreaded spindles for transmitting power to the spindles symmetricallyarranged about Y-axis of the longitudinal carriage and electricalmeasurement-value receivers operably related with the toothed beltdrives and, operative upon a disturbance in the state of equilibrium, todeactivate the drive.
 2. The longitudinal carriage drive as claimed inclaim 1, wherein said electrical measurement-value receivers areelectric generators.
 3. The longitudinal carriage drive as claimed inclaim 1, wherein said electrical measurement-value receivers are lightsensors.